Refrigeration



March 21,- 1944. F. M. RAVER 2,344,922

REFRIGERATION Filed Jan. 13, 1941 3 Sheets-Sheet. l

W I lNyENTOR .Fl'anczs M. fiaver March 21, 1944. M, RA ER 4 2,344,922 I REFRIGERATION Filed Jan; 15, 1941 s Sheets-Sheet 2 INVENTOR Francis M. .R/aver BY 1 2 VM LQ ATTORNEYS March 21,1944. F M RAVER 2,344,922

REFRIGERATION Filed Jan. 13, 1941 :s Sheets-Sheet s INVENTOR Flaricis M flab-er Patented Mar. 21, 1944 2,344,922 REFRIGERATION Francis M. Raver, York, Pm, assignor to Flakice Corporation of New York, Brooklyn, N. Y., a corporation of New York Application JanuarylS, 1941, Serial No. 94,274

12 Claims.

This invention relates 'to improved apparatus for refrigerating material, and more particularly to the refrigeration of material to convert it from a liquid state into a solid state such as the freezing of water to make ice. The present invention (Cl. sz-ros) cylindrical surface.- Then successive portions of the ice sheet are removed from the freezing surface by a radial pushing and wedging action rather than by a tangential scraping or cutting action. Furthermore, the temperature of the ice is an improvement over that disclosed in my coat the point of removal is controlled to regulate pending application Serial No. 307,973. v the hardness and brittleness of the ice to'main- An object of the present invention is to protain these characteristics at such values that the vide improved apparatus for freezing liquids. wedging and pushing action frees the successive Other objects will be in part obvious and in w strips or portions of the ice sheet completely from part pointed out hereinafter. the freezing surface. In the present invention In the drawings: certain aspects of the invention are improved. Figure 1 is aperspective view of apparatus em- Referring to Figure 1,-a tank In or compartbodying the invention and showing diagrammerit containing a tank is shown housing and supmatically a refrigerating system supplying cooled l5 porting a rotatable freezing cylinder generally refrigerant to a rotatable freezing surface; indicated at H and having a cylindrical freezing Figure 2 is a vertical axial section (partly in surface II. -The cylinder, as shown in Figure 2, elevation) taken on line 22 of Figure 1; is rotatably supported in bearing assemblies gen- Figure 3 is an enlarged vertical axial section erally indicated at I3 and I4, respectively, and of a bearing assembly which permits relative is driven from its left end by a gear l5. Liquid movement between a shaft supporting the mrefrigerant compressed in a refrigerating system tatable freezing surface and its bearings, and generally indicated at l6, Figure l, enters the which seals the bearings against escape of the evaporating space of the rotating cylinder refrigerant; and through an inlet connection I! in bearing assem- Figure 4 is a detail diagrammatically showing a bly I3 and the spent gaseous refrigerant leaves spring loaded valve. through an outlet connection l8 in the same bear- The present embodiment of the invention deals ins g w- The temperature of the Surface primarily with the congealing of a liquid, such as I! of the cylinder (evaporator) is maintained at water, on a substantially rigid freezing surface the desired value by means of a reducing valve and the removal of the congealed liquid from I! of usual construction and operated by the the surface in the form of flakes in contradistinctemperature and pressure of the spent refrigertion to finely comminuted ice or "snow which ant. may be scraped from a sheet of ice remaining on The water in the tank is maintained at the dea rigid surface on which it is frozen. The probsired level by any suitable means such as a float lem of removing ice or other aqueous fluids convalve, no sho The D Water cflmil'olled gealed on a rigid freezing surface is difllcult beby the float valve is sprayed onto the surface l2 cause of the tenacity with which the congealed above the water. level through a pipe 20. material clings to the freezing surface, and also As the cylinder ll rotates an ice sheet builds because of the peculiar characteristics of con-' up on the surface I: and is removed by a cutt gealed substances, such, for example, asthe hardwedge unit generally indicated at 2| which in ness, brittleness and tensile and compressive appearance resembles a lawn-mower cutter. It strengths. has a plurality of helical wedging blades and is It has long been recognized that scraping ice mounted in bearings 22 (Figure 2) to rotate freefrom a freezing surface to remove it has many 1y about an axis directly above and parallel to the disadvantages such as consuming considerable cylinder II. The axis is so adJusted that the power and producing a product which because sharp edges of the helical wedges very nearly of its fineness and other qualities is limited in its contact, but do not, the surface l2. As the cyluse as a refrige'ant. Also, in the freezing of foodinder l-I rotates and the surface I: moves past stuffs it is often impractical to subject them to the ice-removing unit 2! the ice on the surface a scraping action because of the damage done to I2 contacts and rotates the wedglng units with the product the result that each helical wedge removes a In the above mentioned co-pending applicatrip of ice from the ice sheet and simultaneously tion there is disclosed a novel method and apps.- frees the ice from the surface I! in the form of ratus for making ice by which the ice is frozen in flakes. As the cylind r continues to rotate. the sheet form on a smooth subs antially ri id metal I 11 8 1 11 n d e removed from the surface I2 by an ice-collecting plate generally indicated at 23. The flakes pass down the plate through a chute 24 provided in the side of the tank II.

The present invention provides for a novel construction of a rotating evaporator, which is is supported on a shaft 25'which runs in the at its inner end through a tube 48 with the bearing assemblies l3 and I4. The cylinder itself is supported on the shaft in the following manner: A sleeve 26 is keyed to the shaft by Woodrufl'" keys generally indicated at 21. secured to the sleeve, as by welding, are two spiders 28. The spiders 28 support on their outer peripheries and are secured to an inner shell 29 of the evaporator. As shown, the inner shell comprises a section of steel pipe provided with a helical groove 30 around its outer periphery. The outer shell 3| of the evaporator and the one which has the surface I2 is preferably of a material such as stainless steel and is shrunk over the inner shell to provide tight contact between the outer shell 3| and helical ribs 32 forming the helical groove 30. The inner and outer shells are welded together around their ends as indicated at 33 to seal the helical space 30 between the inner and outer shells from atmosphere.

The space between the inner shell 29 and the shaft 25 is also sealed from the atmosphere by means of light gage stainless steel heads 34 Welded to the inner periphery of the inner shell along itsedge portions. The heads 34 (Figure 3) are tightly secured with respect to the shaft 25 by clamps 34a which thread on the shaft 25 and clamp the heads 34 between gaskets 3411' and suitable shoulders provided on the shaft 25. The connection of each head both to the inner shell and to the shaft is thus made fluid-tight so that the interior of the cylinder is gas filled and issealed from atmosphere and from the water in the tank Hi. This construction provides the required insulation between the interior of the evaporator and the water in tank ll so that no ice forms on. the heads 34.

The helical groove that runs around the evaporator between the inner and outer shells 29 and at provides the evaporator space in which the evaporation of the liquid takes place to cool the surface l2. The liquid refrigerant enters the helical groove 30 through 'an intake port :35 in 1 bly I3 is shown 'as housed within a split casing.

one section 31 of which extendsthrough and is securedto the sidewall of the tank ll. The other section 38 which might be described as a Suitably cover section is bolted to'the section 31 by suitable bolts, not shown, and a gasket 3! between the sections-makes the fit between the two sec- V tions fluid-tight.

The end of the shaft 2|, extending through the bearing assembly I3 is provided with outer and inner concentric passages 4e and I, respectively. The outer concentric passage has an outlet port 42 which is connected by a tube 43 with the inlet port 35 of the evaporator. The outer concentric passage also has inlet ports 44' which open into an annular passage 45 into which the liquid refrigerant connection l1 opens so that the liquid refrigerant passes to the inlet port 35 through the annular passage 45, the inlet ports 44, the outer concentric passage t0, the port 62 and the vtube 43.

The inner concentric passage ll is connected outlet port 36 of the evaporator groove 30. The outer end of the inner concentric passage opens into a chamber 41 into which the spent refrigerant connection 18 opens. The inner and outer water freezes on the section 31 exposed to the water in the tank "I. Furthermore, this temperature condition is obtained without the use of insulation.

The shaft 25 is supported in the bearing assembly l3 by a ball bearing 5!, the outer race of which is fitted into the section 31, and the inner race 52 of which is secured with respect to the shaft by a clamping ring 53 threaded onto the shaft 25. Thus the bearing 52 not only provides for rotation of shaft 25 but also serves as a thrust bearing to take care of the end thrust caused by the pressure of the refrig- -erant.

The liquid refrigerant is prevented from escaping from the annular passage 45 through to the water in the tank 10 by the following seal construction: Opposed seals 54 and 55 are provided on either side of the ball bearing 5|. The

seals are of known construction and are prefer ably of a spring pressed expanding gasket type with the sealing member 56 being of some material such as rawhide, neoprene," or the like. The seal 54 permits passage of fluid to the left between the seal and the shaft, but resists passage of fluid contrariwise. The seal 55 prevents passage of fluid to the left along the shaft The space between the seals 54 and 55 is.-preferably filled with oil run in from. a chamber 51 through-a line 58 connecting with the space between the seals. As the oil is run in the displaced air is allowed to escape from the space through a passage 59 normally closed by a plug '60.. After the space is filled with oil the chamber 51 is covered and tightly sealed to withstand pressure.

In operation, when the high pressure of the liquid refrigerant reaches the seal 54, it seeps in operation, the seal 54 prevents the pressure that has built up within the space between the two seals from escaping. In this novel manner the pressure of the liquid refrigerant is utilized to accomplish the desirable sealing action.

On the inner end of the section 31 is mounted an additional seal BI adapted to prevent water from the tank I II from reaching the seal 55. And any water which might possibly seep past the seal GI Is drainedout through a passage 42 which empties into the space between the see- I tions 31 and 38.

Next to the seal 54 is provided an additional seal 53 provided to prevent the liquid refrigerant from passing too rapidly into the oil filled space 23 comprises a bent plate, the upper forward surface of which is substantially horizontal. Inasmuch as the ice madeby the machine of the present embodiment may be as thin as one-eighth of an inch or less, the leading edge I0 of the icecollecting plate 23 is positioned closer than oneeighth of an inch to the surface I2 of the cylinder so that the blade picks off the freedice flakes from the cylinder. But since the ice-removing unit 2| does not operate to remove the ice until the ice thickness builds up to approximately one-eighth of an inch, an ice sheet builds u on the surface I2 and moves past the plate 23 during a short period following the putting of the machine in operation. This ice thickness, although not sufficient for the ice-removing unit to operate upon, is sufficient to contact the plate 23 which scrapes on the ice sheet as the cylinder surface I2 moves past the plate. This scraping action puts an abnormally heavy load on the motor rotating the cylinder II and to reduce this load in the present invention the leading edge ID of the plate 23 is serrated as shown in Figure 1. The serrations act to materially reduce the resistance of the scraping action to the cylinder system, as shown, is adapted to work on a rei'rigerant such as dichiorodifluoromethane. The system includes a motor driven comp essor II connected bya line I2 with the outlet connection I8- of the bearing assembly I3. The output of the compressor passes through the usual condenser. diagrammatically shown at 13, whence it passes to a tank diagrammatically shown at I4 in which the liquid refrigerant is stored under a pressure of approximately 125 pounds per square inch and at a temperature which is normally in the'neighborhood of 100 F. Between the tank T4 and the intake connection I I of the bearing I3 is a line generally indicated at I5 in which is provided the usual control valve I9 which in the present embodiment reduces the pressure from approximately 125 pounds per square inch down to 40 or 50 pounds per square inch and simultaneously reduces the tempe ature down to between 40 to 50 degrees Fahrenheit. This control valve is made responsive by a thermo element 16 and connecting line 11 filled with the liquid refrigerant to the temperature of the gas in the line 12. It is also made responsive to the pressure in the line 12 through a line connection 18. The connections I1 and I8 are connected with oppositely acting bellows in the usual manner and the bellows are spring loaded so that the valve I9 passes enough refrigerant to maintain the gas in the line 12 in a super-heated condition as desired.

So that the entering liquid refrigerant may heat the bearing assembly I3 as described, the forty to fifty pound pressure in the line 15a leaving the valve I9 and the corresponding temperature is maintained substantially through to the inlet port 35 of the evaporator by providing suitable means in the line 43 between the outlet port 42 of the concentric passage 48 and the inlet port 35. In the present embodiment this is accomplished by providing a restriction IS in the tube 43 so that the pressure of the refrigerant after leaving the control valve is not allowed to drop until it enters the evaporator proper. Other means of maintaining this pressure could be used, such, for example, as a spring loaded valve in line 43 as shown in Figure 4. By providing this restriction the desired temperatureof the refrigerant necessary to prevent freezing up of the hearing assembly I3 is ensured. Also the system is preferably arranged and adjusted to provide for sufficient velocity of the refrigerant through the pas-,

'sageways in the bearing assembly I3 to ensure adequate heating of the bearing assembly to prevent its freezing up.

Referring to Figure 2, the evaporating groove 30 is provided with a constantly increasing crosssectional area to constantly increase the capacity of the evaporator from the entering end to the leaving end to take care of the increased volume of the fluid as the liquid vaporizes. This increasing capacity of the helix gives the desired increase in velocity of the refrigerant as it passes through the evaporator, which velocity is desirable to ensure the oil present in the l quid refrigerant being carried through the evaporator and back to the compressor, and to ensure adequate and umform cooling of the surface I2 across its entire width. With this-construction, therefore, the evaporator may be run as a series evaporator, thus requiring less refrigerant and a less complicated system than would be necessary if it were run as a flooded evaporator.

Referring again to Figure 1, it is desired to have the tank III as small as possible and to correspond in size closely to that of the cylinder ll. Consequently there is relatively little circulation of the water through the tank and there,is a tendency for the water layer directly beneath the doe-collecting plate 23 to attain a temperature approximately that of 32 F. (when water is being frozen) so that ice particles collect and build up in the water beneath the plate 23. In the present invention this tendency is eliminated by sup-' plying a small amount of heat to the layer of water directly beneath the plate 23. To this end the liquid refrigerant line 15 leaving the tank 14 instead of passing directly to the valve I9 is caused to loop as indicated at 156 in the water layer directly beneath the plate 23. The heat of the liquid refrigerant is sufficient to keep the ice particles fromcollecting or any ice from forming in this area.

Referring to Figure 1 again, there is preferably provided in the line 12 a pressure-responsive switch adapted to cut out the compressor motor drive in the event that the pressure in the line 12 drops below the normal operating pressure as would take place if, for example, the cylinder H stopped rotating and ice started to build up on the cylinder to reduce the heat transfer. Provision of such a safety device ensures against the possibility of the water in the tank III freezing 7 solid and damaging the apparatus.

As various embodiments might be made-of this invention, and as various changes might be made in the construction herein described, all without departing from the scope of the invention, it is to be understood that all matter herein sets forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In ice-making apparatus supplied with re- I frigerant by a compressing system, in combination, a rotatable evaporator, a rotatable shaft for supporting said evaporator, a stationary bearing assembly for supporting said shaft. a passage in said shaft for conducting liquid refrigerant through said shaft to said evaporator and a pas sage in said shaft for conducting gaseous refrigerant from said evaporator through said shaft, the outer ends of said passages respectively opening into separated chambers in said bearing assembly connected respectively with the high and low pressure sides of said compressing system, means in said bearing assembly for preventing said liquid refrigerant from escapin along said shaft to atmosphere including opposing spring pressed seals of the expanding gasket type around said shaft, and means for filling the space between said seals with a viscous liquid miscible with the liquid refrigerant whereby the pressure of the liquid refrigerant raises the pressure of the viscous liquid between the seals, which pressure is thereafter held independently of the refrigerant pressure by the action of said seals.

a rotatable evaporator, a rotatable shaft for supporting said evaporator, a stationary bearing assembly for supporting said shaft, said evaporator and the side of said stationary bearing assembly adjacent said evaporator being exposed to water being frozen, and a passage in said shaft for conducting liquid refrigerant through said shaft to said evaporator and a passage in said shaft for conducting gaseous refrigerant from said evaporator through said shaft, the outer ends of said passages respectively opening into separated passages respectively opening into separated chambers in said bearing assembly and being con-. nected respectively with the high and low pressure sides ofsaid compressing system, in combination, means in said bearing assembly for preventing said liquid refrigerant from escaping along said shaft to atmosphere comprising two opposing spring pressed seals of the expanding gasket type around said shaft, means for filling the space between said seals with a viscous liquid miscible with-the liquid refrigerant whereby the pressure of the liquid refrigerant raises the pressure of the viscous liquid between the seals. which pressure is thereafter held independently of the refrigerant pressure by the action of said seals, and sealing means around said shaft between said spring pressed sealing means-and said water 3. 'In ice-making apparatus supplied with re- 7 means.

, frigerant by a compressing system and including chambers in said bearing assembly and being connected respectively with the high and low pressure sides of said compressing system, in combination, means in said bearing assembly for preventing said liquid refrigerant from escaping along said shaft to atmosphere comprising two opposing spring pressed seals ofthe expanding gasket type around said shaft, means for filling the space between said seals with a viscous'liquid miscible with the liquid refrigerant whereby the pressure of the liquid refrigerant raises the pressure of the viscous liquid between the seals, which pressure is thereafter held independently of the refrigerant pressure by the action of said seals. and a seal in said bearing assembly for preventing water from reaching said first named seals.

4. In ice-making apparatus supplied with refrigerant by a compressing system and including 'a rotatable evaporator, a rotatable shaft for supporting said evaporator: a stationary hearing assembly for supporting said shaft, said evaporator ,and the side of said stationary bearing assembly adjacent said evaporator being exposed to water being frozen, and outer and inner concentric passages' in said shaft for respectively conducting warm liquid refrigerant through said shaft to the evaporator and cold spent refrigerant from said evaporator to the. compressing system, said warm refrigerant serving to keep the bearing assembly above freezing temperature, the outer ends of said passages respectively opening into separated chambers in said bearing assembly, which chambers are connected respectively with the high and low pressure sides of said compressing system, in combination, means in said bearing assembly for preventing said liquid refrigerant from escaping along said shaft to atmosphere -comprising two opposing spring pressed seals of the expanding gasket type around said shaft, means for filling the space between said seals with a viscous liquid miscible with the liquid refrigerant whereby the pressure of the liquid refrigerant raises the pressure of the viscous liquid between theseals, which pressure is thereafter held independently of theiefrigerant pressure by the action of said seals, and another seal in said bearing assembly about said shaft to prevent water from reaching said first named seals, said warm refrigerant serving to keep ice from forming on said last named sealr 5. A rotatable evaporator comprising an inner shell having a helical groove around its outer periphery and an outer shell shrunk over said inner shell to form with the groove an evaporator helical passageway bounded by the outer and inner shells, a shaft, and means for supporting saidevaporator on the shaft. said shaft havingouter and inner concentric passageways for respectively conducting warm-liquid refrigerant through the shaft tothe evaporator and cold spent liquid refrigerant from the evaporator, said warm liquid refrigerant serving to maintain said shaft above the freezing temperature, and end heads for sealing the space between said shaft and said inner shell whereby the interior of the shell is protected from the atmosphere.

6. In ice-making apparatus, in combination, a tank, a cylinder mounted in said tank and rotatable about a horizontal axis, said cylinder having a freezing surface and being over 50% submerged in liquid to be frozen, an ice-freeing unit mounted above said cylinder, and an ice-collecting plate for collecting ice from the cylinder after it is freed from the freezing surface by said icefreeing unit, said collecting plate being slightly above the water level, and means beneath said ice-collecting plate for heating the water therebeneath to prevent ice from collecting in the water under said plate.

7. In ice-making apparatus, in combination, a rotatable evaporator having a freezing surface, a tank for supplying water to said evaporator and in which said evaporator isv partially submerged, an ice-freeing unit for freeing from said freezing surface ice formed thereon, a refrigerant compressing system, a connection for conducting liquid refrigerant from said compressing system to said evaporator, a return connection for conducting the gaseous refrigerant from said evaporator to said compressing system, and a control valve for controlling the supply of refrigerant to said evaporator to maintain the desired temperature-pressure relationship in the return connection, and a pressure-operated switch in said return connection for cutting out the operation of said compressing system in the event that pressure in said return connection drops below a predetermined value.

8. In ice-making apparatus, in combination, a tank, a cylinder mounted in said tank and rotatable about a horizontal axis, said cylinder having a freezing surface over 50% submerged in a liquid to be frozen, an ice-freeing unit mounted above said cylinder for freeing from said freezing surface ice formed thereon, and an ice-collecting plate for collecting ice from the cylinder after it is freed from the freezing surface, said ice-collecting plate being slightly above the water level, and means for heating the layer of water beneath the ice-collecting plate-to prevent ice from collecting in the water under said plate.

9. In ice-making apparatus, in combination,

a tank, a cylinder mounted in said tankand face, said ice-collecting plate being slightly abov. the water level, and means for maintaining the temperature of the layer of water beneath the ice-collecting plate sufiiciently above freezing temperature to prevent ice from collecting in the water under said ice-collecting plate.

10. A rotatable evaporator having an external freezing surface adapted to be supplied with liquid to be frozen, a shaft, said evaporator comprising a shell mounted on said shaft and spaced therefrom and provided with a refrigerant series evaporator passageway close to said freezing surface, and thin uninsulated metal end heads sealed to said shell and said shaft and cooperating therewith to imprison a body of gas within the confines of said shell whereby the heat transfer between refrigerant in said passageway and said end heads is reduced and the temperature of said end heads is kept above freezing temperature.

11. A rotatable evaporator having an external freezing surface adapted to be supplied with liquid to be frozen, said evaporator comprising a shell and having a series evaporator passageway running around said evaporator close to said freezing surface, a shaft for supporting said evaporator provided with outer and inner concentric passageways for conducting liquid refrigerant to and from said evaporator and connections from said respective passageways to an inlet and outlet of said series evaporator passageway, and thin uninsulated metal end heads sealed to said shell and said shaft and cooperating therewith to imprison a body of gas within the confines of said shell whereby heat transfer between refrigerant in said passageway and said end heads is reduced and the temperature of said and heads is kept above freezing tempera- 12. A rotatable evaporator having an external freezing surface, a shaft, said evaporator comat least partially immersed in the liquid in said tank. 1 

